Biomedical subjects
Publications and source records attributed to H J Hönerloh.
Perforation of the footplate in otosclerosis can be performed accurately, when the large and high energetic CO2 laser focus is reduced to 0.5 mm in diameter by an aluminium diaphragm. The operation was performed on three dogs. BAEPs were evoked by bone-conducted acoustic stimuli. Hearing threshold was unchanged immediately after operation as well as after 2 and 6 weeks postoperatively. The new method has still to be performed in man.
Exact knowledge of the upper and lower border of a tracheostenosis is important for success or failure in a transverse resection of the trachea. Using an angular optical equipment of 90 degrees, the upper margin of the stenosis can be focussed endoscopically in case of localisation problems, and projected on the front side of the trachea by the helium-neon laser beam. Even in case of tracheal displacement caused by a tumour, or induration of the soft tissues of the neck due to x-rays, the helium-neon laser beam will be an important orientation aid.
Lidocaine, Mexiletine, Procainamide, and Phenytoin were administered intravenously to anaesthesized rabbits. BERA alterations showed two different patterns. If the intoxication dose was exceeded, amplitude depression, threshold elevation, desynchronization, and severe cumulative prolongation of all latencies and interpeak latencies appeared. Below this dose Lidocaine and Mexiletine induced a single, reversible, dose related, cumulative prolongation of all latencies and interpeak latencies. Procainamide induced counterrelated shiftings of interpeak latencies I-III and III-V, whereas Phenytoin showed no influence. One should, therefore, take into account these effects when BERA is used clinically, since otherwise serious errors can occur. On the other hand, there are diagnostic and therapeutic aspects for the tinnitus patient.
A harpoon-shaped electrode was positioned to the nasopharynx through the nose for registration of BERA-potentials. The amplitudes of peak IV and V increase without changes of latencies. Potential IV is clearer for evaluation of the central conduction time in cases with a single IV/V-complex. Mechanisms of amplitude pattern changes are discussed.
Slow cortical responses to acoustical stimuli are gained by averaging spontaneous electric activity. The influence of different noises makes it difficult to recognize response patterns clearly and without doubt in every case. A method was worked out for faster and more objective recognition of small response patterns with the aid of the statistical sign test.
For better analysis of ERA-potentials it is necessary to eliminate disturbing frequencies by a smoothing filter. For this we propose a special optimized digital filter, which is applicable without falsification of form and amplitude of potentials. Its efficiency will be compared with other smoothing techniques.
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